1. Field of the Invention
The present invention relates to controlling of an ink-jet printing apparatus that can print images on both sides of a sheet.
2. Description of the Related Art
Japanese Patent No. 4,522,156 discusses a printing apparatus that reverses a sheet therein to print images on both sides of the sheet by an ink-jet method. In this apparatus, waiting time until a printing operation start on a second surface (back surface) of the sheet is set based on information regarding an ink application amount to a sheet edge of a first surface (front surface) of the sheet. Jamming or head rubbing may occur when the sheet is conveyed in a cockling state while drying of the ink applied to the first surface is insufficient. The jamming or head rubbing is suppressed with the method discussed in the Japanese Patent No. 4,522,156.
In the printing apparatus discussed in the Japanese Patent No. 4,522,156, the waiting time until the printing start on the second surface is set based on ink applications to at least leading and trailing edges or left and right edges among four side edges of the first surface. Japanese Patent No. 4,522,156 discusses an embodiment of the printing apparatus in which the leading edge and the trailing edge of the sheet are divided into centers (Ea and Eb) and left and right edges (Ea′ and Eb′), and a standby period based on an ink application amount is read from a data table for each area. Then, the longest one of the plurality of read standby periods is selected, and the waiting time until second surface recording is set based on the longest standby period.
In such a configuration, for example, when the ink application amount is large only at the center while there is almost no ink applied to the left and right edges, the occurrence of sheet cockling is not practically a problem. Despite that, long waiting time occurs. Similarly, long waiting time occurs conversely when ink application amounts are large only at the left and right edges while there is almost no ink applied to the center. In other words, there is a possibility that waiting time longer than necessary will be set even for a pattern of a low jamming possibility. The increase of waiting time means reduction of total throughput of two-sided print.